EP1571247B2 - Process for manufacturing mineral wool products, in particular singlelayered and multilayered products - Google Patents

Abstract

A primary web (2) of mineral wool is opened into flocks (9), e.g. by a beater (8), which are then recombined by depositing them on a conveyor (11). The flock size is preferably 10 to 30 mm and can be produced directly or by recombining material after finer opening. The primary web (2) can contain a binder and further materials, e.g. hydroxides or different fibers, can be added in the opened state. The final web (4) can be laid randomly or deposited in a laminar manner. The conveyor (11) is equipped with suction and can include other treatments, e.g. feeding additional material to the edges, to produce a final product.

Description

The invention relates to a process for the production of mineral wool products according to the preamble of claim 1.

For the production of mineral fibers, various methods are known and used, such as internal centrifuging (so-called TEL method), external centrifuging methods such as cascade centrifugal method (so-called REX method), nozzle blowing method and others. In all these known methods, the fibers to be produced by means of large volume flows of a mixture of air and combustion gases, which are required for the extraction of the fibers, in a collection chamber, often called chute, introduced. To produce bonded mineral wool products, the fibers are provided with binder on their way through the chute. Furthermore, other process-relevant substances can be added in the chute, such as dust binders, water repellents and the like.

The fibers thus obtained are deposited on a moving, perforated element, which is one of the boundaries of the chute, and separated from the accompanying gas-air stream. When the fibers are deposited on the perforated element, endless nonwovens are produced in which the properties of the subsequent product which correspond in terms of weight per unit area, width, fiber orientation and homogeneity are predetermined. These properties can not be subsequently changed significantly, so that in the deposition of the chute generated orientations of the fibers in the web or inhomogeneities in the later product are given if the web is not subsequently split or doubled, or separated into adjacent webs.

The weight per unit area is influenced by varying the speed of the perforated separation element with constant fiber input, the fiber orientation generally being essentially laminar. By "laminar" is meant that the fibers are oriented substantially parallel to a surface, usually its support surface. In the production of the web, the total amount of air / gas must pass through the forming web. Depending on the basis weight and the available suction surface, different negative pressures are required in the extraction.

The invention is based on this known production of primary nonwovens made of mineral wool. It has been recognized that so-called inhomogeneities in web formation are virtually unavoidable in any of the known fiberizing processes. These may be inhomogeneities in the wool distribution, with a reduced amount of mineral wool at some points and an increased amount of mineral wool at others. Furthermore, defects such as binder batches or improperly defibred glass parts lead to quality losses.

Also, inhomogeneities of the binder distribution may occur, such as multiply wetted wool accumulations, which had repeatedly passed into the area of the binder spray through backflow, or fiber bundles, which had passed the area of the spraying too fast. Such binder deficiencies or - enrichments are in the final product z. B. recognizable by color differences. To achieve the full functionality of the bond, a larger amount of binder must be added than theoretically necessary because of the inhomogeneous distribution of the binder.

The inhomogeneous wool distribution can also have an effect in locally different basis weights of the nonwoven resulting from locations of different density. Such fluctuations in the wool distribution negatively affect quality features, such as in particular about the heat resistance, but also the mechanical strength. Especially at low densities, in which the areas are visually recognizable with further reduced density, the achievable minimum density is increased by such inhomogeneities, even to avoid visible defects such as "holes". The result must therefore be driven with a higher average density than actually necessary to account for these inhomogeneities of wool distribution. This leads to higher production costs and thus higher product costs and to the reduction of the thermal resistance due to the higher density. Overall, the result is a product that has a quality that differs from the theoretically possible quality.

From the documents EP 1 111 113 A2 . EP 0 434 536 A1 and US 4,632,685 are compressed mineral wool nonwovens become known.

Furthermore, the describes FR 2 682 403 a method for mechanical comminution of a primary web to mineral wool flakes.

From the US 2,589,008 is a process for the production of products made of mineral wool, in which a primary web of loose, binder-free wool or such wool mixed with binder powder is subjected to a mechanical action for reorientation of the individual fibers in several stages in order to produce a final nonwoven with more homogeneous properties. In addition, binder can be sprayed onto this end fleece. In a final hardening step, existing binder is cured in the final web.

The present invention is based on the teaching of FR 2 591 621 A1 from which a method according to the preamble of claim 1 is known. In this known procedure, however, a primary nonwoven with hardened binder is subjected to mechanical comminution.

In contrast, the invention has for its object to provide a method for the production of products made of mineral wool, in which the effects of the different manufacturing processes production-technically unavoidable inhomogeneities in the final product are minimized so that optimal product-specific properties can be achieved with minimal possible mineral wool cost, in particular so that multi-layer products with different properties of the individual layers and high quality single-layer products should be produced.

This object is achieved by a method according to claim 1.

The mineral wool material of the primary nonwoven is crushed mechanically out of its composite into individual mineral wool flakes. These are then deposited again to form the Endvlieses so that the mineral wool material is present isotropically in Endvlies. By isotropic is to be understood here that individual theoretically separated, e.g. Cube-shaped elements of Endvlieses in all directions in the room have the same properties as load capacity and so on. When determining "equal" properties in all directions, it must of course be taken into consideration that mineral wool is composed of randomly arranged and oriented individual fibers and thus statistically unavoidable fluctuations occur.

The preparation of such a product is achieved in that the comminution of the mineral wool material of the primary nonwoven takes place by a combined impact and cutting process.

From the US 3,050,427 For example, there is known a process for producing a composite product of foamed material and mineral fibers, in which a primary non-woven of glass fibers is mechanically digested and then combined with the foaming material to form a plate-shaped end product. With the teaching of this document, the problem to be solved is to arm foamed products by as many reinforcing fibers in the form of glass wool, including a primary non-woven of glass wool comminuted by carding and at the same time admixing the foamable material in this process.

The present invention goes beyond this prior art a very different way: starting from a preferably laminar primary fleece made of mineral wool, which is deliberately crushed into individual mineral wool flakes, to subsequently obtain an improved product, which in its structure consists exclusively of mineral wool again , It has surprisingly been found that individual mineral wool flakes are obtained by a specific comminution of the primary nonwoven, namely by a combined impact and cutting process, which provide a product at a re-deposition to a final nonwoven, which has a lower density compared to the primary nonwoven, but still has at least the other insulation and strength values of the primary nonwoven. This means raw density savings without quality loss.

In this case, the Mineralwollefasem binder is added in the production of the primary web. As a result, the advantages of the method according to the invention also come into play, since hereby also the binder distribution is homogenized, which in particular has an advantageous effect on the strength of the product.

The targeted crushing of the primary nonwoven in certain mineral wool flakes can be achieved in one embodiment of the invention, when the impact and cutting process in their shape differently shaped tines are used, which are part of circumferentially arranged on a roller axially parallel bars and the corresponding during comminution process Combing projections of a downholder for the primary nonwoven with a game. Here, the primary web via a conveyor, in particular a conveyor belt, the impact and cutting process is fed so that it is forcibly guided between the conveyor belt and the hold-down, expediently the conveyor belt and the hold-down run conically to each other.

The tines of the provided on the roller bars can be formed alternately as a percussion finger and a cutting blade, the impact fingers and the cutting blades are to be equipped at their face or cutting edges with a highly wear-resistant coating, as this wear can be minimized, the glassy mineral wool fiber can cause. On the other hand, the tines formed as cutting knives may alternately have different sizes and be aligned with their conical tips in the direction of the roll radius, thereby creating gaps of different sizes for the counterpart in the form of alternating sliding fingers and rod-shaped conveying members. Here, the sliding fingers should be provided rigidly to the hold-down and each extend to near the smaller cutting blade, whereas the rod-shaped conveying members, z. B. designed as endless circulating chains should extend to near the larger cutting blade.

By using the impact fingers, the mineral wool flakes produced during comminution are advantageously precompressed to a certain extent, wherein this precompression may amount to more than 50%, based on the density of the primary nonwoven, eg. B. a raw density increase from originally 30 kg / m ³ to 50 kg / m ³ . It has further been found that the size of the mineral wool flakes produced is of importance in order to obtain an isotropic structure in the final web, and it has been determined from many tests that the mineral wool flakes preferably have an average radial extent of 10 to 30 mm, in particular 15 +/-. 5 mm should have.

When determining the size of the mineral wool flakes produced, it was found that when too large a mineral wool flake is used, the strength of the mineral wool flakes Endvlieses suffers because the individual flakes may have partial areas with a derived from the primary nonwoven laminar fiber structure, which do not have the desired isotropic character, ie these mineral wool flakes do not behave equal under eg same loads from different directions. On the other hand, the bulk density of the end fleece increases when the mineral wool flakes produced are chosen too small in their mean radial extent.

In addition, in the recombination of the mineral wool material to form the Endvlieses the mineral wool flakes advantageously influenced by the precompression randomly stored, so that this random or chaotic distribution counteracts a new formation of inhomogeneities. This results in the end fleece thus a tray, which avoids the production-technically unavoidable inhomogeneities during storage in the chute and thus leads to a considerably more homogeneous product. Furthermore, you get an end fleece, despite the pre-compression of the individual mineral wool flakes in the interaction of chaotic storage, suitable flake size and just pre-compression a lower density at about the same pressure resistance and about the same thermal insulation capacity than the primary nonwoven possessed, which is a significant economic advantage.

Conventional processes for the production of mineral wool products often seek to replace the laminar fiber orientation with a different fiber orientation, which leads to better product properties, in particular with regard to strength. As a result of this fiber orientation, mineral fiber sheets with laminar fiber orientation have low strength against tensile and compressive forces on the large surfaces which seek to squeeze or rupture the sheet. Therefore, mechanical properties such as compressive strength and tear resistance are improved, or as far as required values are achieved even at lower bulk density, when a considerable part of the fibers is perpendicular to the production plane. Widely used for this purpose is an upsetting of the fibers in a compression or crepage system. In this process step, the predominantly horizontally oriented in the production plane fibers are partially oriented in the direction of the vertical before curing of the binder. This results in the longitudinal direction and especially in the thickness direction of the product uncontrolled, random waviness of the fibers and so their reorientation, while in the width direction only a minimal "warping" of the fiber strands or "chains" occurs, and the fibers substantially in their laminar mutual Remain location. The reorientation of the fibers during compression thus takes place in only two dimensions, similar to parallel surface waves on a liquid in which the previously smooth liquid surface only bulges, but the particles on it otherwise remain in the same relative position in the wavelength direction.

Such an effect can also be achieved in the method according to the invention. Characterized in that the mineral wool flakes are deposited substantially chaotically with substantially chaotic fiber orientation in Endvlies, are about equal fiber content in all main directions of the product before. As a result, in contrast to a very fine digestion up to individual fibers is avoided that the fibers occupy again a preferred fiber orientation in the storage to Endvlies. In this way, therefore, as a result of the chaotic storage for the first time a somewhat three-dimensionally compressed product with orientation about the same fiber content in all three main directions can be produced, but the inevitable with the known method disadvantage of a concomitant compression or increase in bulk density is avoided.

It is also known and desirable for many mineral wool products that in the product zones of different densities are generated, such as in order to load the surface of the product stronger. In this case, either a part of the primary web is split off and subjected to a compacting process, upsetting or other solidification and then reunited with the base fleece, or a web produced in a separate chute is moved together with a base fleece after appropriate processing. In the latter case, the nonwoven produced in the separate chute can have different properties, such as higher binder content.

In that regard, it is also advantageous according to the invention that the end fleece with its isotropic structure with at least one other mineral wool material, for. In the form of a nonwoven, to form a composite product. In the simplest case, the mineral wool flakes of the primary nonwoven produced on the other, possibly different mineral wool material can be easily stored and subjected together with this further processing steps such as a compaction and / or an upsetting process and / or a curing process.

There are a variety of ways of combining with other mineral wool layers and the treatment of the individual layers, individually and / or in combination. In this way composite products with very different properties of the layers can be produced, such as a composite product with an inner mineral wool body and at least one stable outer protective layer, the latter does not differ substantially in their bulk density from that of the main body.

So it is z. B. possible to produce the primary web in a separate chute with a higher content of binder and / or other reinforcing substances compared to the other mineral wool material and then combine with the latter. As a result, the strength of the cover layer thus obtained can be further increased even at approximately the same density.

As has been shown, the method according to the invention offers, above all, in a simple manner, the possibility of producing multilayer products which are known by the term bidensity plates, which in particular find their use in flat roofs and on the façade. Here, the product according to the invention is characterized by a layer with isotropic and a layer with laminar fiber structure, wherein the layer having the isotropic structure has a higher compressive strength than the other layer.

Furthermore, products are also possible which are plate-shaped and consist of only one layer, which has an isotropic fiber structure, which z. B. as so-called. Impact sound insulation panels in the screed area can be used.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing.

Fig. 1

in Seitenansicht eine prinzipielle Darstellung des erfindungsgemäßen Verfahrens an einer Zerkleinerungsstation hierfür;

Fig. 2

in Seitenansicht ein Detail des Schlag- und Schneidevorgangs einer bevorzugten Zerkleinerungsstation mit einer Einzelheit "Z",

Fig. 2a

eine Draufsicht auf die Zerkleinerungsstation nach Fig. 2,

Fig. 3

eine schaubildliche Darstellung eines gestauchten Produktes nach dem Stand der Technik unter Zug- und Druckbelastung,

Fig. 4

eine Fig. 3 entsprechende Darstellung eines erfindungsgemäß hergestellten Produktes,

Fig. 5

eine grafische Darstellung der Wärmeleitfähigkeit über der Rohdichte, und

Fig. 6

in einer den Fig. 3 und 4 entsprechenden Darstellung ein erfindungsgemäß hergestelltes Produkt mit verfestigter Oberflächenschicht.

It shows:

Fig. 1

in side view a schematic representation of the method according to the invention at a crushing station for this purpose;

Fig. 2

in side view a detail of the striking and cutting process of a preferred crushing station with a detail "Z",

Fig. 2a

a top view of the crushing station after Fig. 2 .

Fig. 3

a perspective view of a compressed product according to the prior art under tensile and compressive stress,

Fig. 4

a Fig. 3 corresponding representation of a product according to the invention,

Fig. 5

a graphic representation of the thermal conductivity over the gross density, and

Fig. 6

in a the 3 and 4 corresponding representation of an inventively prepared product with solidified surface layer.

In Fig. 1 1, a station designated overall for comminuting mineral wool material of a primary nonwoven 2 is illustrated. The comminuting station 1 is arranged between a conveying direction arrow 3 upstream of the defibering station and a downstream curing oven. The fiberizing station and the curing oven may be of any known type and are therefore not shown in detail.

The primary web 2 is produced in the fiberization station by depositing mineral fibers produced from a melt by means of a large-volume conveying gas air flow on an evacuated perforated element, such as a screen fabric, which is progressively moved in the direction of production. This results in a fiber deposit in the primary web 2 such that the mineral fibers are arranged predominantly parallel to the bearing surface or to the large surfaces of the primary web 2, so to speak, "lie". Such a fiber deposit is referred to as "laminar".

In the example case, to produce a bonded mineral wool product, a binder would have been added to the fiber stream prior to deposition on the perforated element which is cured in a conventional conventional curing oven so as to give the mineral wool product its stable final shape. Between shredding station and curing oven, the binder is still uncured, and the fibers are still movable against each other, and can be influenced in terms of reorientation. For this purpose, it is known to "compress" the mineral wool material in that the primary web 2 is surface increasingly slowed down in an upsetting station, so that the fibers begin to straighten under this compressive pressure and receive in larger numbers a main direction perpendicular to the large areas of the product. As a result, the strength of the product is significantly increased with concomitant increase in density against surface pressure and surface tension, but conversely decreases the flexural strength.

It is also known before driving into the curing oven several primary fleece to drive over each other or sections of the same primary fleece pendulum store each other. As a result, each primary non-woven with only small thickness can be produced under optimized production conditions and then combined to form a more complex, thicker product. Also, this can specifically affect the properties of layers or layers of composite products. The fundamentally laminar fiber deposit does not change as a result. If necessary, a compression (Crepage) can be used.

According to the invention, the shredding station 1 is now arranged between the shredding station and the curing oven. In this, the mineral wool material of the primary web 2 is mechanically comminuted, so singled out of its composite in mineral wool flakes, and then this newly filed to form a Endvlieses 4.

For this purpose, the primary nonwoven 2 runs in the entry into the crushing station 1 by a rotating pressing member 5 in its thickness compressed, and is held by a hold-6 in the compressed state. In this position, a separation of the mineral wool material from the composite of the primary nonwoven 2 out by intervening between the hold-6 tines 7 a Zerflockungswalze 8, which takes place Apply primary fleece 2 from below and separate between gaps in the hold-down 6 to form mineral wool flakes 9.

The individual mineral wool flakes 9 containing fiber stream, denoted by 10, is supplied in the example of a bottom-side perforated conveyor belt 11 and stored on this. In the space 12 below the conveyor belt 11, an air extraction takes place, so that the fiber deposit on the conveyor belt 11 is supported by a large-volume air flow. In this respect, the fiber deposit on the conveyor belt 11 is similar to that on the perforated element in the fiberizing station.

According to the invention, relatively compact flakes are produced in the comminuting station 1, which already experience a certain pre-compaction with respect to the gross density in the primary web 2 due to the action of the prongs 6 meshing with the blank holder 6, the flakes being deposited in a random orientation. Therefore, the fiber orientation in the final web 4 is chaotic, i. isotropic. In the example case after appropriate, not shown further pre-compaction, the material passes with this isotropic orientation in the curing oven in which the binder hardens. Depending on requirements, before the curing oven also a further fiber influencing may take place, for example by a compression.

On the underside of the fiber stream 10, a guide member 13 may be arranged, which in its downstream region, the fiber stream 10 toward its deposit on the conveyor belt 11 leads, and is supported with its upstream end in a manner not shown and between the tines. 7 the flocculation roller 8 engages to prevent formation of fiber accumulations there.

Furthermore, additives such as hydroxides or extraneous fibers may be introduced into the loose fiber stream 10 to create or assist desired properties.

As in the case of web formation in the fiberization station, the nonwoven former comprising the conveyor belt 11 can be provided with side walls which are known per se and can be adjusted in a distance, in order to laterally guide and limit the end web 4. The web forming device can further be added or subordinated to a device for influencing the wool distribution. In particular, at low basis weights of the Endvlieses 4, the wool can be further homogenized in order to even more uniform when filing from the fiber stream 10 occurred inhomogeneities of the wool distribution or bring about a desired wool distribution. For this purpose, the wool distribution can be influenced by locally different effective suction or by air lances or mechanical action as needed.

As will be readily apparent, such comminuting stations 1 can be used in a variety of ways in the area between the refining station and the curing oven. A crushing station 1 can first of all be used wherever previously a compression station was provided. It can also homogenize each individual primary non-woven fabric for itself and thereby isotropically reshaping, after which instead of primary nonwovens 2, the final nonwovens 4 thus formed can be moved over one another or placed on top of each other. But it is also possible to promote 4 further mineral wool material on the conveyor belt 11 in the form of a further primary web 2 or Endvlieses, and to form on the upper side of the end web 4 as a further layer.

The inventive method thus does not limit the applicability of known procedures nowhere, but extends them to the possibility of any fleece, whether inventively or otherwise pretreated or not, as primary fleece 2 supply a crushing station 1 and so in any case to homogenize, and in to transform an isotropic fiber orientation.

The in Fig. 2 and 2a each shown section of a preferred crushing station 1 'shows in side view a Zerflockungswalze 8', the circumferentially a plurality of the same distance from one another and axially parallel strips 14 having, which are provided at their free ends with tines 7 '. The tines 7 'mesh with a hold-down 6' with a play 15 to allow formation of the mineral wool flakes 9 (not shown). The game 15 is in Fig. 2a clearly recognizable and can be adjusted in size.

The designated with 2 'primary web is the impact and cutting process by means of a conveyor belt 12' and a hold-6 'supplied, wherein the conveyor belt 12' and the hold-6 'run conically in the transport direction, so that the primary web 2' is forcibly guided.

The tines 7 'of the strips 14 are formed alternately as a percussion finger 16 and as a kind of cutting blade 17, which are equipped at their impact and cutting surfaces with a highly wear-resistant coating. The cutting blades 17 are again alternately different sizes - 17a; 17b - formed and aligned with their conical tips radially with respect to the Zerflockungswalze 8 '.

The hold-down 6 'in turn has alternately arranged rigid sliding fingers 18, each extending to the vicinity of the smaller, relatively radially projecting cutting blade 17a, and rod-shaped conveying members 19 in the form of endlessly circulating chains, which are up to the vicinity of the larger, radially relative extend inner cutter 17b.

In the actual striking and cutting process for producing the mineral wool flakes 9, the primary nonwoven 2 'on the conveyor belt 12' and the hold-6 'of the flocculation 8' according to the in Fig. 2 forcibly fed in the direction of transport, while the flocculation roller 8 'in the counterclockwise direction as shown in FIG Fig. 2 is driven at about 1000 revolutions per minute, which means a peripheral speed of 32 meters per minute with a mean roller diameter of 800 mm. Here, during comminution of the mineral wool material of the primary web 2 'in mineral wool flakes 9 in particular by the impact fingers 16 a certain pre-densification of mineral wool flakes 9. This pre-compression may be more than 50% based on the density of the primary web 2', ie, for example, an increase in the density in Primarvlies 2 'of 25 kg / m ³ to 50 kg / m ³ in the mineral wool flakes 9 effect. In this case, a preferred average expansion of the mineral wool flakes 9 of 15 +/- 5 mm is achieved, so that the end fleece 4 (not shown) receives an isotropic fiber structure. Due to the initially loose storage of the precompressed mineral fiber flakes 9 on the conveyor belt 11 is advantageously effected that the end fleece 4 has a lower bulk density than the primary nonwoven 2 ', but otherwise about the same parameters (thermal conductivity, mechanical strength).

In Fig. 3 is a diagram of a conventionally compressed plate shown how it is exposed surface tension or surface pressure. As indicated in the drawing, depending on the type of device used for compression, the compression (crepage) leads to a different formation on the side surface of the product 20 designated 21, which was produced in a production direction according to arrow 3. The formation of the side surface 21 ranges depending on the device used by a pronounced waveform to a largely random random position, as in Fig. 3 is illustrated. Such a largely random random position on the side surface 21 can be approximately with a high-performance compression system according to the EP 1 144 742 B1 to which reference is made in full in this respect because of further details.

On the large surfaces 22, however, only a more or less pronounced curl is recognizable, which originates from the compression rollers or compression bands that have introduced the compression forces on these surfaces.

On the other hand, designated at 23 end faces of the product 20, which arise in the lengthening of plates of the cured mineral wool web, however, a laminar deposition of the fibers is still recognizable. All forces encountered during compression have only acted perpendicularly to this end face 23, so that fiber strands or "chains" lying transversely to the production direction according to arrow 3 may possibly have been rotated or tilted so that fibers lying in the direction of production according to arrow 3 are oriented in the direction of the vertical were. However, fibers of the laminar product lying transverse to the direction of production according to arrow 3 were not influenced in their orientation. In that regard, the product 20 is still laminar over its frontal width at the end face 23, even after the compression.

The product 20 must be designed for certain surface tension or surface pressure loads to which it is exposed during use. To achieve these strengths, a certain bulk density must be maintained as the product becomes stronger with higher bulk density. For example, to obtain a surface tensile strength of 30 kN / m ² , the product 20 may require a bulk density of 130 kg / m ³ . In order to achieve a surface compressive strength of 60 kN / m ² , a bulk density of 160 kg / m ³ may be required. Increased bulk density leads to increased use of material and thus increased costs and above a bulk density of about 50 to 70 kg / m ³ to a reduction of the thermal resistance by increasing the thermal bridges to the fibers, so a drop in quality.

In Fig. 4 is an exemplary inventively obtained product 30 in a representation accordingly Fig. 3 shown. The product 30 has been obtained by mechanically comminuting a primary web to form flakes and recombining the flakes into a final web 4 which has been precompressed as desired and then cured in the curing oven to compact it to its final thickness.

In the individual mineral wool flakes 9, the fibers lie in predominantly non-parallel arrangement, but as it has formed the interaction of the tines 7 'with the hold-down 6'. In the fiber stream 10, the flakes are moved against each other and finally deposited randomly on the conveyor belt 11 to form the Endvlieses 4. In this way, the previously laminar fiber deposit of the primary web 2 has been reoriented to a completely random, isotropic fiber deposit in the final web 4. After compression of the Endvlieses 4, the individual mineral wool flakes 9 in Endvlies 4 are no longer recognizable, but the deposited flake mass has become a homogeneous and integral new structure.

Visually, this is evidenced by the fact that the fibers on side surface 31, large area 32 and end face 33 are arranged completely randomly. While at a compression according to Fig. 3 a merely two-dimensional reorientation of the fibers takes place, which leaves the width direction substantially unaffected, takes place in accordance with the invention Fig. 4 Thus, a completely three-dimensional reorientation, which fully covers all three main directions.

This isotropic orientation of the fibers and their freedom from inhomogeneities result in the same binder content as in a compressed plate according to Fig. 3 a surface tensile strength of 30 kN / m ² already at a bulk density of about 95 kg / m ³ , and a surface compressive strength of more than 60 kN / m ² already at a bulk density of about 105 kg / m ³ . This thus results in a reduction of the bulk density of more than 25%, and due to reduced use of materials, a corresponding reduction in product costs.

On the other hand, improved quality results due to improved thermal resistance: For the same dimensions and other parameters of the products according to FIG. 3 and FIG. 4 resulted in the product according to the invention according to Fig. 4 a 4 to 5 mW / (m K) reduced thermal conductivity. In addition to the homogeneous consistency of the product according to the invention according to Fig. 4 The improvement in the thermal conductivity also results from the fact that the reduction of the density above the optimum of about 50 to 70 kg / m ³ regularly leads to a reduction in the material conduction of heat through the fibers and thus to increase the thermal resistance.

At low bulk densities below about 50 kg / m ³ , the thermal conductivity increases inevitably again, since with a lower bulk density of the inclusion of static air inevitably less successful. As you know, products are not insulated by the insulating material itself, but by the static air enclosed by the insulating material. While at high densities, the line through the insulating material itself increasingly comes to the fore and increases the thermal conductivity, this plays at low densities no more significant role, but succeeds the inclusion of a dormant air cushion inevitably worse and worse.

This is in the graph according to Fig. 5 illustrated in more detail. The local dashed line illustrated curve 40 shows a typical course of thermal conductivity above the density in laminar, produced with internal centrifugation mineral wool material. In contrast, the curve 41 shown in a solid line illustrates the corresponding course in a material homogenized by targeted comminution material with isotropic fiber structure and otherwise the same parameters as the wool material of the curve 40. As can be seen, a point A of the same thermal conductivity shifts Material produced according to the invention by an amount a in the direction of reduced bulk density. This means that products which could not fall below a certain density to achieve a desired thermal conductivity, according to the invention can be prepared with respect to reduced bulk density, resulting in corresponding savings. Especially in the case of materials with a high bulk density, such as those used in flat roof insulation, any permissible reduction in the bulk density as a result of the high production quantities results in a considerable cost advantage.

The permissible reduction of the bulk density in the case of light materials results essentially from the homogenization of the wool and binder distribution in the product achieved according to the invention. As a result, the product is always closer to its theoretical ideal state, and it does not need to be driven with material surpluses, just to have sufficient material even at shortage.

Conversely, but also according to Fig. 5 to work at a point B of the same density. Then there is an improvement b of the thermal conductivity, so with the same material use a significant improvement in thermal insulation properties and possibly a better thermal conductivity group.

Finally, both the bulk density can be reduced by a value a ₁ which is lower than the value a and the thermal conductivity can be improved by a value b ₁ which is reduced by comparison with the value b, as shown in FIG Fig. 5 is illustrated by arrow c. This is recommended, for example, if the improvement in the Wämleitfähigkeit to the value b _{1 is} already sufficient to achieve a desired better Wärmeleitfähigkeitsgruppe, so that a further reduction of the thermal conductivity is no longer necessary and instead to the still available value a ₁ at Raw density can be saved.

An essential further field of application of the present invention resides in composite products, wherein the use of the invention can at least always take place where conventionally compression processes (crepage) have been used.

Such a composite product is in Fig. 6 shown as product 50. Such a product, for example a facade insulation board, has a laminar insulating layer 51 and a solid surface layer 52. The solid surface layer 52, usually a compression plate relatively high bulk density, serves to protect the insulating layer 51 against point-like applied forces. In the case of a facade insulation board these forces are applied by retaining dowels, which set the facade insulation board with the solid surface layer outwards against the building wall and hold against gravity and wind forces. For reasons of installation effort is to strive to get along with as few plugs.

In such a case, considerable shear forces occur in the solid surface layer in the region of the edges of the dowel plate, which is indicated at 53. The anchor pull resistance of the facade insulation board results from the capacity of the solid surface layer 52 against these shear forces on the dowel edges.

While the solid surface layer 52 is conventionally made from a compressed plate, it contains a plurality of thickness-directional fibers which avoid indentation of the solid surface layer in the area of the dowel plate 53 (mattress effect) but have very limited strength against shear forces at the dowel edges because they can be relatively easily moved against each other by also acting in the direction of thickness forces. Therefore, very high densities and comparatively high thicknesses of the solid surface layers 52 are required, resulting in an increased required thickness of the entire due to the greatly reduced heat resistance of the solid surface layer Facade insulation board leads.

Will the solid surface layer 52, as shown in Fig. 6 is schematically illustrated, according to the invention produced by the fact that a primary nonwoven fabric 2 selectively crushed to form mineral wool 9 and then recombined into a final web 4, the three-dimensional, isotropic Faserablage results in an orientation of the fibers in all directions. In this way, on the one hand enough fibers are present, which counteract a recess (mattress effect), but also sufficient fibers which extend in the region of the dowel edges transverse to the shear forces introduced there and thus intercept these clean. Thus, on a product corresponding to the product 50, once with compressed solid surface layer and once with flocculated solid surface layer 52 according to the invention measured at the same binder contents and densities Dübeldurchzugsfest, ie that anchor force at which the solid surface layer 52 is pushed or pulled over the anchor plate 53. In the case of the compressed solid surface layer, this comparison test revealed a plug-in tensile force of more than 500 N, but in the case of the solid surface layer 52 produced according to the invention a plug-in tensile force of almost 1000 N.

Thus, the required Dübeldurchzugskraft is already achieved with a solid surface layer 52 according to the invention with significantly reduced thickness and / or bulk density, which accordingly leads to a reduction in the use of material while improving the insulation effect.

In addition, inhomogeneities are present in a solid surface layer of compressed material. These consist for example in areas of higher and lower binder content, ie harder and softer points. Moreover, the bulk density can vary significantly locally. Such inhomogeneities cause the local absorption capacity for shear forces to drop drastically. Thus, if such a density variation comes within the range of a dowel edge, the dowel may rupture, although the dowel pull-through strength of the entire plate, measured at many other locations, is sufficient. For this reason, dowel pull-through resistance in the compressed plate must, so to speak, be "held up" so as to still have adequate dowel pull-through strength even in the event that the dowel comes to sit at a weak point. This in turn leads to higher required thicknesses or bulk densities of the solid surface layer.

Hard hides produced according to the invention are considerably more homogeneous due to the disruption and the associated dissolution of inhomogeneities in the primary nonwoven 2 and have virtually no defects. Both the binder distribution and the wool distribution are considerably more uniform. Thus, the anchor tensile strengths at different points of a facade insulation board also vary only slightly, so that no Dübeldurchzugsfestigkeit "held" must be to compensate for vulnerabilities. This is an additional reason why solid surface layers 52 made in accordance with the invention can manage with still further reduced thicknesses and / or bulk densities compared to the above description.

In addition to a composite product, products of mineral wool, in particular rock wool, which exclusively have an isotropic fiber structure can also be produced by the process according to the invention. A typical application would be so-called tread insulation panels or flat roof insulation panels, the latter can be compressed to a further increase in their compressive strength two- or three-dimensional.

Claims (16)

1. Process for the production of mineral wool products, in which a primary nonwoven with a preferably laminar fibre structure is firstly generated by spraying a binding agent on fibres on their path through a fall shaft, wherein the primary nonwoven is then further processed into a final nonwoven, wherein the mineral wool material of the primary nonwoven (2, 2') is mechanically broken up from its composite structure into mineral wool flocks (9) and the mineral wool flocks (9) are then stacked once again to form the final nonwoven (4) in such a way that after its re-stacking the mineral wool material is present isotropically in the final nonwoven (4), wherein the binding agent is present in still uncured form during the breaking up of the mineral wool material of the primary nonwoven, characterised in that
   the mineral wool material of the primary nonwoven (2, 2') is broken up by means of a combined beating and cutting process, and
   the primary nonwoven (2, 2') is fed to the beating and cutting process by a transport means, in particular a conveyor belt (12'), in such a way that it is guided between the conveyor belt (12') and the pressing holder (6, 6').
2. Process according to claim 1, characterised in that during the beating and cutting process prongs (7, 7') configured in different shapes forming part of bars (14) arranged axis-parallel on the periphery side of a flocking roller (8, 8') mesh with corresponding projections of a pressure holder (6, 6') for the primary nonwoven (2, 2') with clearance (15).
3. Process according to claim 1 or 2, characterised in that the conveyor belt (12') and the pressing holder (6') run conically towards one another in the transport direction.
4. Process according to one of the preceding claims, characterised in that the prongs (7, 7') are configured alternately as beater fingers (16) and as cutting blades (17).
5. Process according to claim 4, characterised in that the beater fingers (16) and the cutting blades (17) are provided with a highly wear-resistant coating on their impact and cutting surfaces.
6. Process according to claim 4, characterised in that the cutting blades (17) are configured to alternately differ in size (17a, 17b) and are respectively oriented radially to the flocking roller (8, 8') with their conical tips.
7. Process according to one of the preceding claims, characterised in that the pressing holders (6, 6') are alternately formed by rigid sliding fingers (18), which respectively extend into the vicinity of the smaller cutting blades (17a), and by bar-shaped transport members (19), which extend into the vicinity of the larger cutting blades (17b).
8. Process according to claim 7, characterised in that endless loop chains serve as bar-shaped transport members (19).
9. Process according to one of the preceding claims, characterised in that during breaking up of the mineral wool material of the primary nonwoven (2, 2') into mineral wool flocks (9), in particular by the breaker fingers (16), the mineral wool flocks (9) are pre-compressed.
10. Process according to claim 9, characterised in that the pre-compression of the mineral wool flocks (9) amounts to more than 50% in relation to the density of the primary nonwoven (2, 2').
11. Process according to one of the preceding claims, characterised in that the mineral wool flocks (9) have an average extent of 10 to 30 mm.
12. Process according to claim 11, characterised in that the mineral wool flocks (9) have an average extent of 10 to 20 mm.
13. Process according to one of the preceding claims, characterised in that the final nonwoven (4) has a lower raw density than the primary nonwoven (2, 2').
14. Process according to one of the preceding claims, characterised in that the final nonwoven (4) with its isotropic structure is combined with at least one further mineral wool nonwoven (51).
15. Process according to claim 14, characterised in that the combination of final nonwoven (4) and the further mineral wool nonwoven (51) are jointly subjected to an upsetting process.
16. Process according to claims 14 or 15, characterised in that the further mineral wool nonwoven (51) has a laminar fibre structure.

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